Elizabethkingia, Situational Awareness, and Astute Clinicians

Amesh A. Adalja, MD, FACP, FACEP, FIDSA, April 29, 2016

Several Midwestern states are in the midst of a mysterious outbreak of bacteremia (and other infections) caused by Elizabethkingia—an environmentally ubiquitous bacterium that is, in rare cases, capable of causing infections in compromised hosts.

Wisconsin, Michigan, and Illinois

In late 2015, Wisconsin’s Department of Health was notified of clusters of infections with Elizabethkingia anopheles. The identification of this cluster of infections triggered epidemic alerts to neighboring states, ultimately resulting in the identification of similar cases in Illinois and Michigan. Total cases now number more than 60 with at least 20 deaths.

Investigation of the source of this outbreak is ongoing, and no common link has been found to date. However, the majority of cases exhibit bacteremia and are above 65 years of age with major underlying health conditions.

Spectrum of Illness

The most well known of the Elizabethkingia genus is E. meningosepticum, an established cause of neonatal meningitis linked to contamination of saline eye flushes, sinks, and ventilator tubing. In rare circumstances, immunocompromised adults can be infected, usually via the respiratory tract through contaminated ventilator tubing. Bloodstream infections, arthritis, and keratitis have also been noted.

Often Elizabethkingia can be resistant to multiple antimicrobial agents with chromosomally encoded metallo-β-lactamases rendering them intrinsically resistant to carbapenems. In the current outbreak, fluoroquinolones, rifampin, and trimethoprim-sulfamethaxazole are likely to be effective based on antimicrobial susceptibility testing. Combination therapy is advised, and contact precautions are being used for hospitalized patients.

Astute Clinicians and Microbiologists

This outbreak illustrates how, in the right circumstances, a rare pathogen can cause a deadly multistate chain of infections. Astute clinicians and microbiologists who detected aberrancy in the expected rate of Elizabethkingia infections in Wisconsin were an essential component in bringing this outbreak to light and identifying its full extent. The unfolding of this outbreak highlights the absolute importance of having situational awareness of outbreaks in a community, a state, and a region. The most pressing need to control this outbreak is to determine the source of exposure and, once identified, to attempt to minimize this risk in the future.